perf: on-demand sourcemap generation

[h-a-n-a]

Summary

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

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[h-a-n-a]

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📝 Benchmark detail: Open

Name	Base (2024-05-08 65224fb)	Current	Change
10000_development-mode + exec	2.74 s ± 26 ms	2.76 s ± 23 ms	+0.79 %
10000_development-mode_hmr + exec	695 ms ± 20 ms	702 ms ± 7.2 ms	+1.01 %
10000_production-mode + exec	2.51 s ± 26 ms	2.55 s ± 26 ms	+1.67 %
arco-pro_development-mode + exec	2.51 s ± 50 ms	2.51 s ± 83 ms	+0.04 %
arco-pro_development-mode_hmr + exec	430 ms ± 2 ms	430 ms ± 2.4 ms	+0.06 %
arco-pro_development-mode_hmr_intercept-plugin + exec	440 ms ± 1.6 ms	442 ms ± 6.1 ms	+0.40 %
arco-pro_development-mode_intercept-plugin + exec	3.33 s ± 84 ms	3.3 s ± 50 ms	-0.66 %
arco-pro_production-mode + exec	4.03 s ± 93 ms	4.05 s ± 111 ms	+0.30 %
arco-pro_production-mode_intercept-plugin + exec	4.84 s ± 81 ms	4.9 s ± 60 ms	+1.10 %
threejs_development-mode_10x + exec	2 s ± 22 ms	2.04 s ± 13 ms	+2.04 %
threejs_development-mode_10x_hmr + exec	768 ms ± 8.4 ms	771 ms ± 8.2 ms	+0.34 %
threejs_production-mode_10x + exec	5.18 s ± 18 ms	5.23 s ± 25 ms	+1.10 %

[pushkargupta9807]

can we please have more info on this perf improvement PR ? For instance how can we use it , examples etc

[chenjiahan]

@h-a-n-a please check this ⬆️

[h-a-n-a]

can we please have more info on this perf improvement PR ? For instance how can we use it , examples etc

This is an internal optimisation where source maps should always be generated on-demand by builtin:swc-loader with the respect to the compiler's source map options. I didn't make a real world benchmark, but this will improve the case where options.devtool set to false.